Final answer:
A mixture is a combination of two or more substances that can be separated by physical means. The substances retain their individual identities and no chemical reaction occurs between them.
Step-by-step explanation:
Mixture: A mixture is a combination of two or more substances that can be separated by physical means. In a mixture, the individual substances retain their own identities and no chemical reaction occurs between them. Examples of mixtures include air (a mixture of different gases) and cereal in milk.
The main characteristics of mixtures are that the substances that make them up are not in a fixed ratio, these substances keep their physical properties, and they can be separated from each other using mechanical means such as filtration or distillation.